I think that people look at DBM::Deep and go "It can't be that simple, so it's got to be really hard cause I don't understand it." This is your code, with the changes needed to make it DBM::Deep'ed.

# First script, to populate the db file:
use DBM::Deep;

our %services;
tie %services, 'DBM::Deep', 'file.db';

%services = (
    1 => {
        name => "service1",
        host => { host1 => 1 },
    },

    2 => {
        name => "service2",
        host => { host0 => 2, host5 => 2 },
    },
);

######################

# Second script, to print the services.

our %services;
tie %services, 'DBM::Deep', 'file.db';

print "----------------Menu-----------------------------------------\n
+";
print "Please enter the number of the service and press return\n";
print "-------------------------------------------------------------\n
+";
for $row (sort keys %services){
        my $service=$services{$row};
        print "$row\t $service->{ name }\n";
}
print "Please enter number -->";
[download]

That's it. Note that your usage of %services doesn't change at all.